1. Field
Embodiments of the present invention relate to a display device, and more particularly, to a transparent display device.
2. Description of Related Art
Display devices are classified into liquid crystal display (LCD) devices, organic light emitting diode (OLED) display devices, plasma display panel (PDP) devices, electrophoretic display (EPD) devices, and the like, based on a light emitting scheme thereof.
With recent development in electronics technology, various types of display devices are being widely used. Among these, in particular, a transparent display device displays a character or an image while maintaining visual transparency thereof.
Examples of display elements applicable to such a transparent display device may include an OLED element, an LCD element, an EPD element, and the like. Among these, an OLED element is gaining attention as a suitable display element for a transparent display device due to various advantages thereof in terms of a viewing angle, a contrast, response speed, power consumption, and the like.
Such a transparent display device using an OLED element includes a display area and a transmission area. The display area includes a thin film transistor, various signal connecting wirings, an electrode wiring, an organic light emitting material, and the like, disposed therein; and the transmission area includes a transparent substrate, a transparent insulating layer, and the like, disposed therein.
In a switched-off state of a transparent display device, an object or an image behind the display device (e.g., positioned opposite to a user) is transmitted through the transparent display device to be visible to the user. However, even in the case of the transparent display device, due to a low level of transmittance of a thin film transistor and various wirings of a display area and a limited space occupied by a transmission area, an overall level of transmittance of the transparent display device is relatively low.
It is to be understood that this background of the technology section is intended to provide useful background for understanding the technology, and as such, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to a corresponding effective filing date of subject matter disclosed herein.